|Original Message (ID '127477') By Chenyu Lue:|
|Since you use NDSolve to solve your differential equation, all variables, except x and y, must have the definite values.
So please check your input clearly.
By the way, since a and b are related to x and y and you want to get the x[t] and y[t], why not define a and b as 4.721 - y[t] and 9.20566 + 1.85*t - x[t] respectively?
Hope this will help you!|